---
sidebar_label: patch
description: |-
  The "kv patch" command writes the data to the given path in the key-value
  store. The data can be of any type.
---

# kv patch

:::warning

**NOTE:** This is a [K/V Version 2](/docs/secrets/kv/kv-v2) secrets
engine command, and not available for Version 1.

:::

The `kv patch` command writes the data to the given path in the K/V v2 secrets
engine. The data can be of any type. Unlike the `kv put` command, the `patch`
command combines the change with existing data instead of replacing them.
Therefore, this command makes it easy to make a partial updates to an existing
data.

## Examples

If you wish to add an additional key-value (`ttl=48h`) to the existing data at
the key "creds":

```shell-session
$ bao kv patch -mount=secret creds ttl=48h
== Secret Path ==
secret/data/creds

======= Metadata =======
Key              Value
---              -----
created_time     2019-06-06T16:46:22.090654Z
deletion_time    n/a
destroyed        false
version          6
```

**NOTE:** The `kv put` command requires both the existing data and
the data you wish to add in order to accomplish the same result.

```shell-session
$ bao kv put -mount=secret creds ttl=48h passcode=my-long-passcode
```

The data can also be consumed from a file on disk by prefixing with the "@"
symbol. For example:

```shell-session
$ bao kv patch -mount=secret creds @data.json
```

Or it can be read from stdin using the "-" symbol:

```shell-session
$ echo "abcd1234" | bao kv patch -mount=secret foo bar=-
```

## Usage

### Output options

- `-field` `(string: "")` - Print only the field with the given name. Specifying
  this option will take precedence over other formatting directives. The result
  will not have a trailing newline making it ideal for piping to other
  processes.

- `-format` `(string: "table")` - Print the output in the given format. Valid
  formats are "table", "json", or "yaml". This can also be specified via the
  `BAO_FORMAT` environment variable.

### Command options

- `-method` `(string: "patch")` - Specifies the patch method to use. Valid
  methods are `patch` and `rw`. The `patch` method uses an HTTP `PATCH` request
  to apply the partial update. The `rw` method will fetch the secret's data,
  perform an in-memory update, and write the updated data.

- `-cas` `(int: 0)` - Specifies the value to use for the Check-And-Set operation.
  This flag will only be used for the `patch` method. This flag is required if
  `cas_required` is set to `true` on either the secret or the engine's config.
  In order for a `patch` to be successful, `-cas` must be set to the current
  version of the secret. This flag will be ignored for the `rw` method.
  Instead, its value will be derived from fetching the current version of the
  secret.

- `-mount` `(string: "")` - Specifies the path where the KV backend is mounted. 
  If specified, the next argument will be interpreted as the secret path. If 
  this flag is not specified, the next argument will be interpreted as the 
  combined mount path and secret path, with /data/ automatically inserted for 
  KV v2 secrets.
